Absorbent article with controlled distribution of liquid

ABSTRACT

A disposable sanitary towel (1) comprising a liquid-permeable upper layer (5), an impermeable lower layer (7) and an absorbent element (6), is provided with an intermediate layer (10) disposed between the upper layer (5) and the absorbent element (6) and extending around the side edges (8) of the absorbent element (6) such that it can distribute the liquid received and prevent losses of liquid from the side edges of the absorbent element (6). The towel (1) is further provided with an absorbent element (6) comprising an improved layer structure.

BACKGROUND OF INVENTION

The present invention relates to a sanitary towel generally consistingof an upper layer which is permeable to liquids, a lower layer which isimpermeable to liquids and an absorbent element disposed between them.

More particularly, the invention relates to a sanitary towel thestructure of which comprises one or more layers intended to control thedistribution of the liquid which is deposited on the surface of theupper layer facing the user's body.

Preferred arrangements of the invention comprise an absorbent elementwhich contains hydrogelling absorbent material as a component, andpreferably as the principal component.

Sanitary towels having an upper layer which is permeable to liquids, animpermeable lower layer and an absorbent element which is disposedbetween them and contains hydrogelling absorbent material are known inthe prior art.

The patent U.S. Pat. No. 5,009,653 describes a sanitary towel comprisingan upper layer which is permeable to liquids, a lower layer which isimpermeable to liquids and an absorbent element disposed between them,the absorbent element consisting of a layered structure consisting oftwo dry-formed external tissue layers and of a central layer ofhydrogelling absorbent material.

A layer for collecting the liquid, consisting of a non-woven fabric, 70%of which is composed of rayon and 30% of which is composed of polyesterfibres, is disposed between the upper layer and the absorbent elementand is intended to improve the sideways distribution of the liquidpassing through the upper layer. The sideways distribution of the liquidin the collecting layer increases the surface area of the absorbentelement to which the released liquid can have access, but, on the otherhand, it is possible for the liquid to migrate to the edges of thesanitary towel such that it can spot and stain the user's underclothesin certain conditions of use.

The patent EP-A-257280 describes a composite covering layer for anabsorbent article, such as a sanitary towel, in which a substantiallyhydrophobic perforated polymer film which is less than 0.762 mm thickand has a total open area of at least 35% is disposed on a layer ofnon-woven fabric secured thereto, the openings in the first layer havingdimensions which are insufficient to allow the passage of a 1% salinesolution under the effect of gravity alone, whilst the second layer hasa capillary structure such that it allows a rise of less than 12.7 mm of1% saline solution after 15 minutes.

The absorbent article comprises an absorbent element having atwo-layered composite structure, in particular a low-density upper layerformed of cellulosic fibres and a lower layer consisting of ahigh-density mixture of cellulose fibres and superabsorbent material.

The lower side of the absorbent element is secured to a polyethylenesheet which extends to the side edges of the absorbent element toprevent the fluid being able to pass from the base and side edges of theabsorbent element to the user's underclothes.

It should be noted that the composite covering layer enables the liquidto flow in a single direction to ensure improved properties with respectto the backflow of liquid, and it is further noted that the said layerdisplays very poor diffusion properties, or a low ability fortransmitting the liquid in a sideways direction.

The present invention seeks to avoid the disadvantages of anintermediate layer which is completely permeable to liquids, at the sametime retaining the ability to distribute the liquid received to zones ofthe absorbent element remote from the area where it is collected.

OBJECT OF INVENTION

It is therefore an object of the invention to produce a sanitary towelhaving a layered structure which enables the liquid released over thesurface of the said sanitary towel facing the users body to becontrolled.

It is also an object of the invention to produce a sanitary towel havingan absorbent element disposed between a lower layer which is impermeableto liquids and an upper layer which is permeable to liquids and ontowhich the liquid is released, in which an intermediate layer disposedbetween the upper layer and the absorbent layer distributes the releasedliquid over the surface of the absorbent element facing the user's body,however it is arranged such that losses of liquid from the side edges ofthe towel towards the user's underclothes are prevented.

It is a further object of the invention to produce a sanitary towel inwhich an intermediate layer disposed between the upper layer and theabsorbent element distributes the liquid released onto the surfacefacing the body of the user of the absorbent element, the intermediateelement extending around the side edges of the absorbent element, atleast at its central portion so as to enable the liquid to be diffused,at least along the internal surface of the intermediate layer, aroundthe longitudinal side edges of the absorbent element, the intermediatelayer furthermore being arranged such that losses of liquid from theside edges of the absorbent element towards the user's underclothes areprevented.

It is an even further object of the invention to produce a sanitarytowel having an upper layer which is permeable to liquids, a lower layerwhich is impermeable to liquids and an absorbent layer comprised betweenthem, the sanitary towel further comprising a hydrophilic intermediatelayer disposed between the upper layer and the absorbent element, inwhich the absorbent element comprises a layered structure in which thedensity of the respective layers decreases from the upper layer to thelower layer.

In accordance with the present invention, these objects are achievedwith a sanitary towel having the characteristics specifically mentionedin the following claims.

A sanitary towel according to the present invention is characterized inthat the absorbent element is covered on its surface facing the user'sbody and along its side edges with an intermediate layer which comprisesa part which is substantially impermeable to liquids, at the side edgesof the absorbent element, and a part substantially permeable to liquids,on at least a pan of the surface of the absorbent element facing theuser's body.

Preferably, the sanitary towel according to the present inventioncomprises an intermediate layer having a bulk of more than 5 cm³ /g, acapillary diffusion capacity of less than 150 seconds in the "horizontaldiffusion test", and an absorption capacity of less than 1 g in the"free absorption test".

Preferably, the sanitary towel according to the present inventioncomprises an absorbent element formed of a first, a second and a thirdfibrous layer, the first fibrous layer having a greater density thanthat of the second fibrous layer and the third fibrous layer having alower density than that of the first and second fibrous layers.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described purely by way of non-limitingexample with reference to the appended drawings, in which:

FIG. 1 is a plan view of a sanitary towel produced according to thepresent invention, viewed from its side which is to face the user;

FIG. 2 is a view in section of the towel along the line II--II in FIG.1;

FIG. 3 is a view in partial section of a preferred arrangement of theintermediate layer comprised in the towel according to the presentinvention;

FIGS. 4 and 5 are views in section of two alternative arrangements of atowel according to the present invention;

FIG. 6 is a view in section of three alternative arrangements for thesingle absorbent element incorporated in the sanitary towel according tothe present invention;

FIG. 7 is a view in section of a further alternative arrangement of atowel according to the present invention, comprising an absorbentelement of a type illustrated in FIG. 6;

FIG. 8 is a view in section of a further alternative arrangement of asanitary towel 1 according to the present invention;

FIG. 9 is a plan view of a further arrangement of the sanitary towelproduced according to the present invention, viewed from the side whichis to face the user, with the upper layer omitted and part of thestructure being incomplete;

FIG. 10 is a view in section of the towel along the line II--II in FIG.9;

FIG. 11 is a view in section of a sanitary towel with side wingsproduced according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to disposable absorbent articles and moreparticularly to ladies'sanitary towels which are worn in direct contactwith the body externally of the user's vulvar region, which can absorbbody fluids, and which are subsequently disposed of after a single use.

The present invention is not, however, restricted simply to sanitarytowels but also applies to other disposable absorbent articles, such as,for example, so-called panty liners and the like.

The disposable sanitary towel illustrated in FIGS. 1 and 2 represents apreferred embodiment of an absorbent article produced according to thepresent invention.

FIG. 1 illustrates a sanitary towel 1, produced according to the presentinvention with a portion of the structure removed to show theconstruction more clearly; in particular it shows the upper side of thetowel which, in use, is in direct contact with the user's body.

FIG. 1 shows a front region 2, a rear region 3 and a central region 4comprised between them; there is further shown a longitudinal axis AA'and a transverse axis corresponding to the sectional line II--II.

The towel comprises an upper layer 5 which is permeable to liquids andwhich is to contact the user's body directly, an absorbent element 6,and a lower layer 7 which is impermeable to liquids.

In the arrangement illustrated, the towel is shaped such that it has agreater width at the from region 2 and the rear region 3, with theresult that it is narrower in the central region 4; as is known, thisshape permits improved adaptability to the user's anatomy; the absorbentelement 6 is rectangular with rounded ends and with straightlongitudinal side edges 8 which are parallel to one another, and ischaracterized by a width which is slightly smaller with respect to theminimum width of the towel in correspondence with the central zone 4.

The liquid-permeable upper layer 5 and the impermeable lower layer 7 arethe same shape and size as the external shape of the whole absorbentproduct and are joined to each other, for example by means of a glued orheat-sealed line, along at least the outer contour 9 of the towel.

The liquid-permeable upper layer 5 should enable the liquid to passquickly through its thickness towards the structure below; it can beproduced in various ways known from the prior art, for example fromnon-woven fabric, however, a perforated polymeric film which ispermeable to liquids but is not absorbent is preferred.

In a preferred arrangement of the present invention, the surface of thepermeable upper layer 5 facing the users body is hydrophilic,particularly in the case in which the upper layer 5, is produced with aperforated polymer film.

The hydrophilic surface ensures a quicker passage of the liquid throughthe upper layer 5, towards the underlying absorbent structure and alsoreduces the possibility of some of the liquid itself running over thesurface of the upper layer.

The surface of the permeable upper layer 5 facing the body can berendered hydrophilic by treatment with a surfactant, applied for exampleby spraying or by means of a roller.

Alternatively, the surfactant can be incorporated directly into thematerial from which the permeable upper layer 5, is formed.

The absorbent element 6 is covered by an intermediate layer 10 whichcovers the surface facing the user's body and, at least in the centralregion 4 of the towel 1, the longitudinal side edges 8 of the absorbentelement 6 by means of the two longitudinal marginal portions 11; asillustrated in FIG. 2, the intermediate layer 10 preferably compriseslongitudinal marginal portions 11 of a width such that they also extendpartially in correspondence with the side of the absorbent elementfacing the underclothing.

The intermediate layer 10 is substantially impermeable to liquids in thelongitudinal marginal portions 11 which wrap around the longitudinalside edges 8 and at least part of the surface, facing the underclothing,of the absorbent element 6, and comprises a portion 12 which issubstantially permeable to liquids on at least pan of the surface of theabsorbent element 6 facing the user's body.

The intermediate layer 10 is characterized by high bulkiness, greaterthan 5 cm³ /g, and preferably good capillary diffusion of the liquid anda low absorption capacity.

The capillary diffusion capacity and the absorption capacity of thematerial constituting the intermediate layer are assessed by means of a"Horizontal diffusion test" and a "Free absorption test", both performedon rectangular samples of material which are 80 mm long and 25.4 mmwide, using a 0.9% by weight saline solution.

For each test, the values obtained represent the average of the valuesmeasured for three equivalent samples.

Horizontal Diffusion Test

An apparatus is used which is known as a "Demand wettability tester",illustrated in "Absorbency", edited by Pronoy K. Chatterjee andpublished by Elsevier Science Publishers B.V., ed. 1985, page 62, withreference to B. M. Lichstein, "INDA Technical Symposium," U.S.A., 1974,page 129.

The test is performed by placing on the horizontal test plate a sampleof material having the agreed dimensions with one end at level with thehole through which the liquid is released with a hydrostatic head ofapproximately zero.

The time taken by the liquid to reach the other end of the samplecovering the distance of 80 mm is measured in seconds.

Free Absorption Test

The sample with the agreed dimensions is weighed and then placedcarefully on the surface of the liquid; the surface of the materialfacing the surface of the liquid is the surface of use.

The sample is left on the liquid for 1 minute, is then raised at one endwith forceps, is left to drip for one minute and is finally weighedagain.

The difference between the initial weight and the final weightrepresents the amount of liquid absorbed freely by the sample beingtested.

The material constituting the intermediate layer 10 should have acapillary diffusion time, measured according to the "Horizontaldiffusion test", of less than 150 seconds and a free absorptioncapacity, measured according to the "Free absorption test" of less than1 g, and preferably of less than 0.5 g.

The use of the covering structure for sanitary hygiene products,described in the EP-B-207904 in the name of the same Applicants,rendered hydrophilic by means of suitable treatment, has provedparticularly preferable.

The structure, illustrated in particular in FIG. 3, is generallyperforated and comprises an upper layer 13 consisting of a non-wovenfabric, an intermediate layer 14 consisting of a polymeric film and alower layer 15 consisting of a non-woven fabric; the three layers arecombined together to form a structure having a thickness of between 200μand 700μ.

In a preferred embodiment of the present invention, the fibresconstituting the non-woven fabric of the upper layer 13 and lower layer15 of the layered structure constituting the intermediate layer 10 areof the hydrophilic type, for example rendered such by means of suitabletreatment with surfactants before the structure itself is formed; inaddition, the entire structure is perforated and thus rendered permeableto liquids, only in the portion 12 of the intermediate layer 10, whilstthe longitudinal marginal portions 11 covering the longitudinal sideedges 8 and at least part of the surface, facing the underclothing, ofthe absorbent element 6, are not perforated and are thus substantiallyimpermeable.

In use, the structure can receive and transmit the liquid quicklythrough the holes in the permeable portion 12, from the permeableoverlying upper structure 5 to the underlying absorbent element 6.

The high bulkiness of the intermediate layer 10 isolates the permeableupper structure 5 from the surface of the absorbent element 6, helpingto keep the surface of the towel facing the user's body dry during use.

The unperforated longitudinal marginal portions 11 of the intermediatelayer 10 prevent losses of liquid which might occasionally occur at thelongitudinal side edges 8 of the absorbent element 6, when the sanitarytowel is subject to the normal pressures of use.

The capillary diffusion capacity of the upper fibrous layer 13 and lowerfibrous layer 15, together with the low liquid absorption capacity, aresuch that some of the liquid received through the overlying upper layer5 is transmitted by capillarity to the interior of the fibrous layersremote from the zone in which the liquid itself is initially received,typically in the centre of the permeable portion 12, being diffused bothin the longitudinal and in the transverse directions.

In this way, the surface area of the intermediate structure 10 throughwhich the liquid passes towards the underlying absorbent element 6 isincreased, with the advantage of a greater extent of the absorbentelement being involved in the absorption of the liquid.

In addition, the liquid migrating along the intermediate layer 10 in thetransverse direction is conveyed beyond the side longitudinal edges 8 ofthe absorbent element 6 until it reaches the lower surface of theabsorbent element 6, at least as far as where the longitudinal marginalportions 11 of the intermediate layer 10 extend below the absorbentelement 6.

Thus, some of the liquid can also be absorbed through the lower surfaceof the absorbent element 6.

The liquid preferably advances along the surface of the intermediatelayer 10, internally facing the absorbent element 6, corresponding, inthe preferred embodiment, to the lower fibrous layer 15 of the layeredstructure in FIG. 3, since it arrives there both by internal capillaryaction through the fibres and by the absorbent element 6, for examplebecause of possible losses from the longitudinal side edges 8.

The low liquid absorption capacity of the material of which theintermediate layer 10 is composed is such that only a minimum amount ofliquid is retained inside the structure, the greater part, on the otherhand, being conveyed to the absorbent element 6 by the method described.

A lower, stopping layer 16 is preferably comprised between the absorbentelement 6, possibly partially enveloped by the intermediate layer 10 incorrespondence with the surface facing the underclothing, and theimpermeable lower layer 7.

As FIG. 1 shows, the lower, stopping layer 16 preferably has the sameshape as the sanitary towel 1 and thus, at the front zone 2 and the rearzone 3, it is wider than the rectangular absorbent element 6, formingfour portions 17.

The lower, stopping layer 16 is preferably hydrophobic and has a verylow capillary diffusion capacity; in a preferred arrangement, the layeris formed of the same perforated layered structure which constitutes theintermediate layer 10, with the fibres of the fibrous layers 13 and 15being hydrophobic instead of hydrophilic.

Small amounts of liquid which may be absorbed by the absorbent element 6and successively released during use from the lower face facing theunderclothing, or migrating at the base along the external surface ofthe intermediate layer 10, can be received by the lower, stopping layer16 inside the small cavities constituted by holes and retained therewithout being able to diffuse anywhere else by virtue of the hydrophobicnature of the fibres of which the layer is composed.

In addition, the four portions 17 of the lower, stopping layer 16 which,at the front region 2 and rear region 3 of the shaped towel 1, extendsideways relative to the longitudinal side edges of the rectangularabsorbent element 6, and provide the sanitary towel 1 with greaterconsistency and thickness in the zones.

The absorbent element 6 can be produced from a large variety ofabsorbent materials commonly used in sanitary towels, babies'nappies andother disposable-type absorbent articles.

Suitable materials may be cellulose fibres obtained from wood pulp,absorbent foams or sponges, synthetic fibres, hydrogelling absorbentmaterials or any material or combinations of equivalent materials.

Hydrogelling absorbent materials, commonly known as superabsorbents, arepolymers which can swell up and absorb large quantities of liquid,particularly water, or also, to a lesser extent, body fluid

They also have the particular property that they retain the fluids evenunder moderate pressure; owing to this characteristic, their use incombination with hydrophilic fibres for disposable absorbent articleshas been proposed for some time.

The high absorption capacity of superabsorbents is not, however,combined with similarly rapid absorption and this may adversely affectthe performance of absorbent articles incorporating these substances.

In fact, superabsorbents may give rise to a phenomenon defined, in theprior art, as "gel blocking": when a particle of superabsorbent is incontact with the liquid, its external surface starts to absorb theliquid and swells up, obstructing the transmission of the liquid intothe particle itself; the liquid can penetrate further into the still-drycore of the particle only by means of a very slow diffusion mechanism.

This phenomenon may prevent full use being made of the large absorptioncapacities of superabsorbent substances.

In any case, with the use of hydrogelling absorbent materials, it ispossible to produce absorbent elements which contain fewer hydrophilicfibres for a given absorption capacity and which consequently arecharacterized by smaller dimensions, particularly thicknesses thanconventional absorbent elements made of fibres alone

Structures have been formed in which the fibres and the particles ofhydrogelling, absorbent material are disposed in separate, superposedlayers, generally characterized by a greatly reduced thickness.

A thin, layered absorbent structure such as the one described in patentapplication TO92A000566 of 3rd Jul. 1992 is particularly preferred as anabsorbent element for the sanitary towel of the present invention.

The above absorbent structure is formed of two or more fibrous layersand, between each pair of the fibrous layers, there is an intermediatelayer comprising particles of hydrogelling absorbent material andparticles of thermoplastic polymeric organic material; the fibrouslayers extend sideways beyond the respective intermediate layers,forming longitudinal marginal portions.

The fibrous layers, comprising between them the respective intermediatelayers, are joined together by melting of the particles of thermoplasticorganic material and by means of continuous lines of adhesive extendinglongitudinally, at least in correspondence with each longitudinalmarginal portion.

The absorbent element 6, illustrated in FIG. 2, is a preferredarrangement of the thin layered absorbent structure described.

The absorbent element is composed of a first fibrous layer 18, a secondfibrous layer 19 and a third fibrous layer 20, and of two intermediatelayers 21 comprising a mixture of particles 22 of hydrogelling absorbentmaterial and thermoplastic polymeric organic material.

The surface distribution of the particles 22 forming the intermediatelayers 21 may be non-uniform, in particular, in the example described inthe patent application EP 92306824.1 of 27th Jul. 1992, the absorbentelement 6 may comprise a central longitudinal collection zone 23 and twoside zones 24 positioned between the collection zone 23 and thelongitudinal side edges 8, with a lower concentration of thehydrogelling absorbent material, comprised in the intermediate layers21, in the longitudinal central collection zone 23 than in the two sidezones 24.

In the preferred embodiment illustrated in FIG. 2, the firstintermediate layer 21, between the first and second fibrous layers 18and 19 respectively, comprises the central longitudinal collection zone23 in which the particles 22 are distributed at a lower surface densitywith respect to the remaining part of the intermediate structure itselfand with respect to the entire second intermediate layer 21 comprisedbetween the second and third fibrous layers 19 and 20, respectively.

In the preferred arrangement illustrated in FIG. 2, the longitudinalcentral collection zone 23 is completely free from particles 22.

FIG. 2 also shows continuous lines of adhesive 25 which extendlongitudinally both along the longitudinal marginal portions of thelayered structure, located, in the arrangement illustrated, at thelongitudinal side edges 8 of the absorbent element 6, and along theedges of the longitudinal central collection zone 23.

The fibrous layers composing the layered absorbent structure illustratedin FIG. 2 are not equal to one another: in particular, the density ofthe layers decreases progressively from the first fibrous layer to thethird.

Preferably, the first and second fibrous layers 18 and 19 respectivelyconsist of dry formed ("air laid") layers of short cellulose fibres,whilst the lower fibrous layer 20 is formed of cellulose fibres andsynthetic fibres and is thermally stabilised ("thermobonded"); thepresence of the synthetic fibres provides the layer with elasticity andbulk.

In use, the more dense upper layers 18 and 19 receive the liquid and cantransmit it quickly towards the underlying layers of fibres andhydrogelling absorbent materials, at the same time distributing itlongitudinally and transversely so as to increase the area of theunderlying layers involved in absorption. The longitudinal central zone23, without hydrogelling absorbent material, comprised in the firstintermediate layer 21, permits quicker collection of the liquid which,at least in this zone, is thus transmitted quickly and directly from thefirst fibrous layer 18 to the second layer 19.

Being more bulky, the lower fibrous layer 20 has a lower diffusioncapacity but can take in a greater quantity of liquid, thus contributingto the overall absorption capacity of the entire absorbent element 6together with the particles of hydrogelling absorbent material of theintermediate layers 21.

Furthermore, by virtue of the elasticity provided by the presence ofsynthetic fibres, it does not tend to collapse when it is wet; smallamounts of liquid which can escape from the lower fibrous layer 20 whenthe absorbent is subject to normal pressures of use can, however, bereabsorbed by the particles of hydrogelling absorbent material of theoverlying intermediate layer 21.

The following FIGS. 4 to 11 illustrate some alternative arrangements fora sanitary towel produced according to the present invention, theelements common thereto being indicated with the same numerals used inFIGS. 1 and 2.

FIGS. 4 and 5 illustrate two alternative arrangements for the sanitarytowel of the present invention which both differ from the preferredarrangement in FIG. 2 by the lack of the lower stopping layer 16.

In addition, in the arrangement in FIG. 5, the intermediate structure 10is completely wrapped around the absorbent element 6, with thelongitudinal marginal portions 11 partially overlapping the underside ofthe absorbent element for increased protection against possible lossesof liquid from the base of the absorbent element itself.

FIG. 6 illustrates some alternative arrangements for an absorbentelement 6, which is to be incorporated in a sanitary towel produced inaccordance with the present invention, in which the absorbent element isproduced from a layered absorbent structure formed by two fibrouslayers, one upper layer 26 and one lower layer 27, with theinterposition of an intermediate layer 21 comprising hydrogellingabsorbent material and comprising continuous lines of adhesive 25 atleast at the longitudinal side edges.

The initial layered absorbent structure is wider than the resultantabsorbent element 6 which is obtained by the folding back ontothemselves of the two longitudinal ends of the layered structure at thetop, as shown in 6a, or at the bottom, as shown in 6b and 6c.

In all three drawings, the resultant absorbent elements show alongitudinal collection zone 23, longitudinal side edges 8 and two sidezones 24 positioned between the collection zone 23 and the side edge 8.

In arrangements 6a and 6b, the side zones 24, characterized by thepresence of a greater amount of hydrogelling absorbent material, areproduced from two overlapping layers of the same layered absorbentstructure, whilst the collection zone corresponds to the central portionof the absorbent element 6 characterized by the presence of a singlelayer of the layered absorbent structure.

In arrangement 6c, the longitudinal ends folded back under the layeredabsorbent structure are extended such that they almost touch one anotheralong the respective longitudinal edges, generally along thelongitudinal axis of the absorbent element itself; the longitudinalcentral collection zone 23 is such that it comprises a zone without anyhydrogelling absorbent material inside the intermediate layer 21, whichis also defined by the lines of adhesive 25.

The two fibrous layers composing the layered absorbent structure inFIGS. 6a, 6b and 6c can have various densities, with the upper layer 26being more dense than the lower layer 27.

In a more preferred manner, the upper fibrous layer 26 consists of adry-formed ("air laid") layer of short cellulose fibres, whilst thelower fibrous layer 27 is formed of cellulose fibres and thermallystabilised ("thermobonded") synthetic fibres.

Layered absorbent structures of the type equivalent to those describedcan, however, be produced in different ways, for example by combiningand superposing fibrous layers having different widths, possible withthe interposition of intermediate layers comprising hydrogellingabsorbent material.

FIG. 7 illustrates an alternative arrangement of a sanitary towelproduced according to the present invention and incorporating anabsorbent element of the type illustrated in FIG. 6, having theintermediate layer 10 completely wrapped around the absorbent elementand having the lower, stopping layer 16.

In this case, the absorbent element comprises a further upper collectionlayer 28, positioned such that the longitudinal ends 29 are below therespective longitudinal ends of the layered absorbent structure foldedback over the top.

The density of the upper collection layer 28 is preferably greater thanthat of the upper fibrous layer 26, which is also constituted, forexample, by a dry-formed layer of short cellulose fibres.

In general, the density of the fibrous layers forming the absorbentelement 6 is preferably between 0.04 g/cm³ /and 0.20 g/cm³.

In this case, the central collection zone 23 of the absorbent element ischaracterized by the presence of the further collection layer 28.

In use, the upper collection layer 28 firstly receives the liquid, inthe central collection zone 23, and transmits it quickly to theunderlying layers, distributing it at the same time in longitudinal andtransverse directions; the liquid can thus reach the longitudinal ends29 of the upper collection layer positioned below the folded-back endsof the absorbent structure, and from there be absorbed into the layeredabsorbent structure, passing both upwards and downwards.

An absorbent element 6 to be incorporated in a shaped-type sanitarytowel produced according to the present invention can itself be shapedin the same manner as the external contour of the entire sanitary towel1.

FIG. 8 illustrates a first arrangement of a sanitary towel of this type;the absorbent element is of a type similar to that illustrated in FIGS.2, 4 and 5, but it is composed of a layered absorbent structure formedof superposed fibrous layers 18, 19 and 20 which are wider than theintermediate layers 21 between them and defined by continuous lines ofadhesive 25; the intermediate layer 10 is simply superposed on theabsorbent structure 6 and preferably has straight and parallel edges anda width which is slightly less than the minimum width of the absorbentelement.

In this way, a shaped absorbent element 6 of suitable form can beproduced without the cutting line affecting the intermediate layers 21;at the front region 2 and the rear region 3 of the towel, the fibrouslayers 18, 19 and 20 extend beyond the continuous line of adhesive 25which is defined by the intermediate layers 21, providing the structureof the towel with increased consistency and thickness in this zone.

A preferred embodiment, illustrated in FIGS. 9 and 10, enables a shapedabsorbent element to be produced which has an intermediate layer 10which is to cover the longitudinal edges 8 of the absorbent element 6and part of the lower surface facing the user's body, at least at thecentral region 4 of the sanitary towel 1.

The absorbent element is produced from a layered absorbent structureformed of superposed fibrous layers 18, 19 and 20 which are wider thanthe intermediate layers between them and defined by continuous lines ofadhesive 25, on which is superposed an intermediate layer 10 of the samewidth as the layered absorbent structure, with the substantiallypermeable zone 12 having a width corresponding to that of theintermediate layers 21.

As illustrated in the plan view in FIG. 9, the portions 30 of the entirestructure to be folded back under the structure itself, and formed bythe fibrous layers 18, 19 and 20 of the absorbent element 6 and of thelongitudinal marginal portions 11 of the superposed intermediate layer10, are defined by four oblique cuts 31 and by two longitudinal foldlines 32.

FIG. 10 shows the manner in which the portions 30 are folded back underthe absorbent structure along the fold lines 31.

A sanitary towel according to the invention, whether it is shaped ornot, may also comprise side wings; as is known, when in use, a sanitarytowel with side wings is positioned inside the user's underclothing andis, if necessary, secured there whilst the side wings are folded backunderneath the underclothing and secured to the external surface thereofin the crotch area.

FIG. 11 shows the manner in which side wings 33 can be produced inaccordance with the present invention, a sufficiently wide, suitableintermediate layer 10 being suitably folded in an "omega" shape belowthe absorbent element 6.

In the arrangement illustrated, each wing 33 is formed by superposingthe permeable upper layer 5, the intermediate layer 10 and theimpermeable lower layer 7.

A sanitary towel according to the present invention may compriseembossing lines which involve the absorbent element 6 only or the entirestructure of the sanitary towel 1, characterized by a substantiallylongitudinal development.

The object of the embossing lines can be to facilitate the diffusion ofthe liquid in the longitudinal direction inside the absorbent element 6,creating local densification zones in the structure itself, or also torepresent preferred fold lines such that, in use, the sanitary toweladopts a preferred manner of folding, for example in the shape of a "W"such that it can be better adapted to the user's anatomy.

All the individual layers forming the structure of the sanitary towel ofthe present invention are preferably secured to one another, forexample, by means of adhesive.

Naturally, the principle of the invention remaining the same, thedetails of construction may be varied widely from those described andillustrated without thereby departing from the scope of the presentinvention.

What is claimed is:
 1. A disposable absorbent article having a frontregion, a rear region, and a central region therebetween, the absorbentarticle comprising a hydrophilic, liquid pervious topsheet, saidtopsheet having a body facing surface consisting essentially of ahydrophilic material, a liquid impervious backsheet and an absorbentcore disposed between the topsheet and the backsheet, the core havingtwo longitudinal side faces, a body facing surface and a garment facingsurface, the body facing surface and the longitudinal side faces of thecore being covered by an intermediate layer, wherein the intermediatelayer comprises a substantially liquid impervious part overlying theside faces of the core at least in the central region of the absorbentarticle and a substantially liquid pervious part overlying at least apart of the body facing surface of the core.
 2. A disposable absorbentarticle according to claim 1 wherein an exterior surface of theintermediate layer is hydrophobic at least at the parts of theintermediate layer overlying the side faces of the core.
 3. A disposableabsorbent article according to claim 1 wherein a barrier layer islocated between the backsheet and the core.
 4. A disposable absorbentarticle according to claim 1 wherein the core is formed with at leastone longitudinally extended embossed line.
 5. A disposable absorbentarticle according to claim 1 wherein the intermediate layer at leastpartly overlies the garment facing side of the core.
 6. A disposableabsorbent article according to claim 5 wherein the intermediate layerfully extends across the body-facing side, the garment facing side, thegarment-facing side and the side faces of the core.
 7. A disposableabsorbent article according to claim 1 wherein the core comprises afirst, a second and third fibrous layer, the first fibrous layer beingof higher density than the second fibrous layer, the third fibrous layerbeing of lower density than the first and second fibrous layers.
 8. Adisposable absorbent article according to claim 7 wherein the thirdfibrous layer comprises thermobonded fibers.
 9. A disposable absorbentarticle according to claim 1 wherein the intermediate layer has a bulkgreater than 5 cm³ /g.
 10. A disposable absorbent article according toclaim 9 wherein the intermediate layer has a bulk greater than 7 cm³ /g.11. A disposable absorbent article according to claim 9 wherein theintermediate layer comprises a laminate of a liquid impervious film anda non-woven material, the non-woven material forming a fibrous wickinglayer on the inner surface of the intermediate layer.
 12. A disposableabsorbent article according to claim 11 wherein the intermediate layercomprises a three-layer structure, comprising a central polyethylenefilm and two outer polypropylene fibrous layers.
 13. A disposableabsorbent article according to claim 11 characterized in that theliquid-pervious part of the intermediate layer comprises perforations.14. A disposable absorbent article according to claim 1 the corecomprising two longitudinal sides, characterized in that the corecomprises a central, longitudinal acquisition zone and two side zoneslocated between the acquisition zone and the longitudinal sides, thecore further comprising an absorbent gelling material, the concentrationof absorbent gelling material in the acquisition zone being lower thanthe concentration of absorbent gelling material in the side zones fortransport of liquids in a substantially longitudinal direction of thecore.
 15. A disposable absorbent article according to claim 14 whereinthat the core comprises two fibrous layers between which the absorbentgelling material is comprised, the weight of absorbent gelling materialper unit surface area of the fibrous layer being lower in theacquisition zone than in the side zones of the core.
 16. A disposableabsorbent article according to claim 14 wherein the core comprises atleast two fibrous layers in the acquisition zone between which theabsorbent gelling material is disposed, the side zones at thebody-facing side of the core comprising at least one more fibrous layerand at least one more layer of absorbent gelling material than theacquisition zone.
 17. A disposable absorbent article according to claim16 wherein the core is folded over along its longitudinal sides so thateach side zone comprises at least two pair of fibrous layers, a layer ofabsorbent gelling material being comprised between each pair of fibrouslayers.
 18. A disposable absorbent article according to claim 16 whereinthe fibrous layers are mutually connected by an adhesive along thelongitudinal sides of the core and along the sides of the acquisitionzone.
 19. A disposable absorbent article according to claim 16 wherein alayer of acquisition material is located between the first pair offibrous layers and the second pair of fibrous layers.
 20. A disposableabsorbent article according to claim 16 wherein the density of eachfibrous layer lies between 0.05 and 0.15 g/cm³.